I will take issue here. It is true that they all have the same minimum protection standard, but that standard does not tell anything about how much the helmet exceeds that standard.

I was stupid one time and messed up a $50 helmet with some solvent based glue. I decided to get another helmet and eventually used the damaged helmet for some backyard testing.

I can safely report that the higher end helmets with the bonded microshell (like most companies higher end road and mountain helmets) will stay together after an impact. The polystyrene will crack, but the bonded shell holds the pieces together. This effectively means that if the helmet is still held in place on the head after an impact, it will still be around to absorb a second (in a different spot of course).

I also know that a helmet with a taped shell will shatter on impact and is not around to absorb another blow as my father (John Ratliff who also posts here) found out when he had his recent accident.

This is one of the problems with the bike helmet industry. Since the design of all helmets are carried out by private companies, the companies are hardly in a position to say whether one helmet in their line is better than another, much less how much better. All they can say is that all their helmets pass a minimum standard. Thus the consumer has no information about which helmet to buy other than vague statements like "best used for road," and price.

I have seen protection ratings for laptop computer bags, but could you imagine trying to choose between a "superior protection" $150 helmet verses a "minimum protection" $20 helmet if you are tight on a budget?